The present application is based on and claims priority from Japanese Patent Applications: 2000-261110 filed Aug. 30, 2000; and 2001-131377, filed Apr. 27, 2001; the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a system for controlling an engine-starting starter.
2. Description of the Related Art
Recently, an economy-run system has been employed in an automotive vehicle in order to improve fuel consumption of the vehicle and to reduce engine exhaust gases of vehicle engine. Such an economy-run system stops an engine whenever the vehicle makes a stop. In such a economy-run system, the engine is stopped according to a condition such as vehicle speed, open angle of accelerator, brake condition, etc. As soon as the brake pedal is eased up and the accelerator pedal is depressed, the starter is operated to start the engine, thereby starting the vehicle.
However, if a pinion gear of the starter abruptly engages a ring gear of the engine while the starter is rotating an engine at a normal speed, the starter may not start up the engine quickly due to a shock caused by the engagement. Such a conventional economy-run system takes a considerable time to fully start up the engine after making a stop. According to a report of the National Police Agency, traffic jam may be expected in a city where many vehicles are running if such a starting time becomes longer than a certain time. Therefore, it is necessary to shorten the engine starting time.
In such an economy-run system, the engine is stopped and started so frequently that the starting noise becomes harsh to an ordinary user of a vehicle. However, it is not sufficient to suppress such the starting noise by a noise absorption material or noise insulating material. A large amount of such materials may increase the vehicle weight and fuel consumption rate of the vehicle. Therefore, it is also necessary to decrease the starting noise.
The present invention has been made in view of the above-stated problem and has an object of providing a starter control system that can shorten the engine starting time and reduce the starting noises caused while the engine is being started.
According to a main feature of the invention, when an engine is driven or rotated by a starter, a starter motor rotates at a preliminary speed that is lower than a normal rotation speed.
If the engine is rotated at a suitable rotation speed that is lower than the normal speed for a predetermined period before it is rotated at a normal operation speed, the engine can fully start up more quickly. When the key switch is turned on, the starter rotates at the preliminary speed and the pinion of the starter engages the ring gear of the engine at a suitable low speed. Therefore, the rattling gear noise caused during the engagement is small. Because the engine is preliminary rotated at a suitable low speed for a predetermined period, noise caused during tottering cranking operation of the engine due to a large inertia thereof or fluctuation of pistons reciprocating between a bottom dead point and the top dead point of the engine can be reduced. Thus, the harsh noise during the engine cranking can be reduced. As a result, the engine starting time can be shorten and the noises can be reduced.
According to another feature of the invention, the preliminary rotation speed is changeable according to an engine condition.
According to another feature of the invention, the preliminary rotation period is changeable according to an engine condition.
According to another feature of the invention, the rotation speed is changed by a variable resistor or an electronic conduction element.
According to another feature of the invention, the engine condition is detected by an engine temperature sensor.